How to Prevent (And Clean) Cloudy Glasses from the Dishwasher

If your glasses come out cloudy after dishwashing, you may have an issue with hard water or etching. Hard water stains may be cleaned by soaking in vinegar, but etching is unfortunately permanent. Here's how to determine the cause and prevent it from happening in the first place.

Why Are My Glasses Cloudy?

There are two primary causes of glassware cloudiness: hard water and etching. Hard water reduces the strength of detergent, making it more difficult to clean glassware, and the minerals present in hard water can also leave a cloudy film on glass themselves. Etching refers to permanent erosion of glassware and has multiple causes.

It's crucial that you figure out which issue you are dealing with first, and then you can determine how to prevent it in the future.

The "vinegar method" is a simple test that reveals whether cloudiness if from hard water or etching. Soak your glassware in vinegar for five minutes. If the cloudy film disappears, it was due to hard water. If the film remains, it's due to etching and is permanent.

How to Prevent Hard Water Deposits

One of the most common causes of cloudy dishes and glassware is hard water or water with high mineral content. The problem with hard water is twofold.

First, minerals in the water reduce the effectiveness of detergents, so more detergent may be needed to get the dishes clean. Hard water also doesn't rinse as well as soft water, with the result of a film of soap or dirty water left on the dishes. Paradoxically, adding too much detergent with hard water only compounds the rinsing problem. Second, the minerals in hard water can dry onto the surface of glassware, creating a cloudy film.

If you have hard water, there are a few things you can try:

Add More Detergent

More detergent may be effective at removing hard water deposits from your glasses. At the same time, using too much detergent may leave a soap film on the dishes, so experiment with different amounts to find the best balance. Dishwasher boosters can be added to the pre-wash cycle to remove hard water spots. This solution is great because it can work with any old washing machine.

Use a Rinse Aid

Rinse aids come in solid and liquid forms. They help reduce spotting and etching by breaking the bond between water and the dishes. Most rinse aids are added with each dishwashing load.

Check Your Water Temperature

Run the water at your kitchen sink for one minute (to avoid waste, run it into a bucket to water your plants later). Put a candy thermometer in a glass and run water into the glass to measure your incoming water temperature. Many dish detergent manufacturers as well as the American Cleaning Institute recommend a temperature of 130 degrees Fahrenheit, but rather than turning up your water heater unnecessarily high, use the high-temp setting on your dishwasher to heat the water no higher than 140 degrees Fahrenheit. If your water heater is far from the kitchen and it takes a while for the hot water to arrive, run the kitchen faucet for a minute or so until the water is hot, then turn on the dishwasher.

Dishwasher with Built-In Water Softener

If you live in a hard water region, you might want to consider upgrading your dishwasher to a model with a built-in water softener. Bosche, Miele, and Whirlpool all make models with built-in softeners where you add dishwashing salts to the special chamber in the machine and it releases the salts during the rinse cycle to keep the water from creating spots on the glasses as they dry.

How to Prevent Etching

If the cloudy film on your glassware isn't removed by the vinegar, your glasses may be etched. Etching is a wearing away of the glass material, resulting in tiny pits and scratches that cannot be removed. It can be caused by very soft water, very hot water, too much (or the wrong kind of) detergent, or excessive pre-cleaning of dishes.

There are a few ways to control etching on your glassware:

Don't Rise or Prewash So Heavily

Modern dishwashing detergents contain harsh alkaline salts that are neutralized by oils and food particles on the dishes. If you remove all food residue from dishes before loading the dishwasher, the detergent has nothing to neutralize it, resulting in a harsher effect on the dishes themselves.

Use Less Detergent

This is especially true if you have soft water. Less soap is needed with soft water, so experiment with different amounts of detergent until you have just enough to get the dishes clean.

Try a Different Detergent

Some detergents cause etching more than others, depending on the softness of the water and other factors. Try a milder detergent (with a lower pH number) or a detergent without phosphates.